37  * DOC: drm panel
39  * The DRM panel helpers allow drivers to register panel objects with a
48  * drm_panel_init - initialize a panel
49  * @panel: DRM panel
50  * @dev: parent device of the panel
51  * @funcs: panel operations
53  *	the panel interface (must NOT be DRM_MODE_CONNECTOR_Unknown)
55  * Initialize the panel structure for subsequent registration with
58 void drm_panel_init(struct drm_panel *panel, struct device *dev,  in drm_panel_init()  argument
64 	INIT_LIST_HEAD(&panel->list);  in drm_panel_init()
65 	INIT_LIST_HEAD(&panel->followers);  in drm_panel_init()
66 	mutex_init(&panel->follower_lock);  in drm_panel_init()
67 	panel->dev = dev;  in drm_panel_init()
68 	panel->funcs = funcs;  in drm_panel_init()
69 	panel->connector_type = connector_type;  in drm_panel_init()
74  * drm_panel_add - add a panel to the global registry
75  * @panel: panel to add
77  * Add a panel to the global registry so that it can be looked up by display
80 void drm_panel_add(struct drm_panel *panel)  in drm_panel_add()  argument
83 	list_add_tail(&panel->list, &panel_list);  in drm_panel_add()
89  * drm_panel_remove - remove a panel from the global registry
90  * @panel: DRM panel
92  * Removes a panel from the global registry.
94 void drm_panel_remove(struct drm_panel *panel)  in drm_panel_remove()  argument
97 	list_del_init(&panel->list);  in drm_panel_remove()
103  * drm_panel_prepare - power on a panel
104  * @panel: DRM panel
107  * the panel. After this has completed it is possible to communicate with any
112 int drm_panel_prepare(struct drm_panel *panel)  in drm_panel_prepare()  argument
117 	if (!panel)  in drm_panel_prepare()
120 	if (panel->prepared) {  in drm_panel_prepare()
121 		dev_warn(panel->dev, "Skipping prepare of already prepared panel\n");  in drm_panel_prepare()
125 	mutex_lock(&panel->follower_lock);  in drm_panel_prepare()
127 	if (panel->funcs && panel->funcs->prepare) {  in drm_panel_prepare()
128 		ret = panel->funcs->prepare(panel);  in drm_panel_prepare()
132 	panel->prepared = true;  in drm_panel_prepare()
134 	list_for_each_entry(follower, &panel->followers, list) {  in drm_panel_prepare()
137 			dev_info(panel->dev, "%ps failed: %d\n",  in drm_panel_prepare()
143 	mutex_unlock(&panel->follower_lock);  in drm_panel_prepare()
150  * drm_panel_unprepare - power off a panel
151  * @panel: DRM panel
153  * Calling this function will completely power off a panel (assert the panel's
155  * is usually no longer possible to communicate with the panel until another
160 int drm_panel_unprepare(struct drm_panel *panel)  in drm_panel_unprepare()  argument
165 	if (!panel)  in drm_panel_unprepare()
170 	 * - Your panel driver incorrectly calls drm_panel_unprepare() in its  in drm_panel_unprepare()
172 	 * - You are using panel-edp or panel-simple and your DRM modeset  in drm_panel_unprepare()
173 	 *   driver's shutdown() callback happened after the panel's shutdown().  in drm_panel_unprepare()
177 	if (!panel->prepared) {  in drm_panel_unprepare()
178 		dev_warn(panel->dev, "Skipping unprepare of already unprepared panel\n");  in drm_panel_unprepare()
182 	mutex_lock(&panel->follower_lock);  in drm_panel_unprepare()
184 	list_for_each_entry(follower, &panel->followers, list) {  in drm_panel_unprepare()
187 			dev_info(panel->dev, "%ps failed: %d\n",  in drm_panel_unprepare()
191 	if (panel->funcs && panel->funcs->unprepare) {  in drm_panel_unprepare()
192 		ret = panel->funcs->unprepare(panel);  in drm_panel_unprepare()
196 	panel->prepared = false;  in drm_panel_unprepare()
200 	mutex_unlock(&panel->follower_lock);  in drm_panel_unprepare()
207  * drm_panel_enable - enable a panel
208  * @panel: DRM panel
210  * Calling this function will cause the panel display drivers to be turned on
216 int drm_panel_enable(struct drm_panel *panel)  in drm_panel_enable()  argument
220 	if (!panel)  in drm_panel_enable()
223 	if (panel->enabled) {  in drm_panel_enable()
224 		dev_warn(panel->dev, "Skipping enable of already enabled panel\n");  in drm_panel_enable()
228 	if (panel->funcs && panel->funcs->enable) {  in drm_panel_enable()
229 		ret = panel->funcs->enable(panel);  in drm_panel_enable()
233 	panel->enabled = true;  in drm_panel_enable()
235 	ret = backlight_enable(panel->backlight);  in drm_panel_enable()
237 		DRM_DEV_INFO(panel->dev, "failed to enable backlight: %d\n",  in drm_panel_enable()
245  * drm_panel_disable - disable a panel
246  * @panel: DRM panel
248  * This will typically turn off the panel's backlight or disable the display
254 int drm_panel_disable(struct drm_panel *panel)  in drm_panel_disable()  argument
258 	if (!panel)  in drm_panel_disable()
263 	 * - Your panel driver incorrectly calls drm_panel_disable() in its  in drm_panel_disable()
265 	 * - You are using panel-edp or panel-simple and your DRM modeset  in drm_panel_disable()
266 	 *   driver's shutdown() callback happened after the panel's shutdown().  in drm_panel_disable()
270 	if (!panel->enabled) {  in drm_panel_disable()
271 		dev_warn(panel->dev, "Skipping disable of already disabled panel\n");  in drm_panel_disable()
275 	ret = backlight_disable(panel->backlight);  in drm_panel_disable()
277 		DRM_DEV_INFO(panel->dev, "failed to disable backlight: %d\n",  in drm_panel_disable()
280 	if (panel->funcs && panel->funcs->disable) {  in drm_panel_disable()
281 		ret = panel->funcs->disable(panel);  in drm_panel_disable()
285 	panel->enabled = false;  in drm_panel_disable()
292  * drm_panel_get_modes - probe the available display modes of a panel
293  * @panel: DRM panel
296  * The modes probed from the panel are automatically added to the connector
297  * that the panel is attached to.
299  * Return: The number of modes available from the panel on success, or 0 on
302 int drm_panel_get_modes(struct drm_panel *panel,  in drm_panel_get_modes()  argument
305 	if (!panel)  in drm_panel_get_modes()
308 	if (panel->funcs && panel->funcs->get_modes) {  in drm_panel_get_modes()
311 		num = panel->funcs->get_modes(panel, connector);  in drm_panel_get_modes()
322  * of_drm_find_panel - look up a panel using a device tree node
323  * @np: device tree node of the panel
326  * tree node. If a matching panel is found, return a pointer to it.
328  * Return: A pointer to the panel registered for the specified device tree
329  * node or an ERR_PTR() if no panel matching the device tree node can be found.
333  * - EPROBE_DEFER: the panel device has not been probed yet, and the caller
339 	struct drm_panel *panel;  in of_drm_find_panel()  local
346 	list_for_each_entry(panel, &panel_list, list) {  in of_drm_find_panel()
347 		if (panel->dev->of_node == np) {  in of_drm_find_panel()
349 			return panel;  in of_drm_find_panel()
359  * of_drm_get_panel_orientation - look up the orientation of the panel through
361  * @np: device tree node of the panel
364  * Looks up the rotation of a panel in the device tree. The orientation of the
365  * panel is expressed as a property name "rotation" in the device tree. The
403  * drm_is_panel_follower() - Check if the device is a panel follower
407  * a panel using the panel follower API.
409  * The "panel" property of the follower points to the panel to be followed.
411  * Return: true if we should be power sequenced with a panel; false otherwise.
416 	 * The "panel" property is actually a phandle, but for simplicity we  in drm_is_panel_follower()
420 	return of_property_present(dev->of_node, "panel");  in drm_is_panel_follower()
425  * drm_panel_add_follower() - Register something to follow panel state.
427  * @follower:     The panel follower descriptor for the follower.
429  * A panel follower is called right after preparing the panel and right before
430  * unpreparing the panel. It's primary intention is to power on an associated
432  * devices are allowed the follow the same panel.
434  * If a follower is added to a panel that's already been turned on, the
438  * The "panel" property of the follower points to the panel to be followed.
441  *         follower_dev is not actually following a panel. The caller may
442  *         choose to ignore this return value if following a panel is optional.
448 	struct drm_panel *panel;  in drm_panel_add_follower()  local
451 	panel_np = of_parse_phandle(follower_dev->of_node, "panel", 0);  in drm_panel_add_follower()
455 	panel = of_drm_find_panel(panel_np);  in drm_panel_add_follower()
457 	if (IS_ERR(panel))  in drm_panel_add_follower()
458 		return PTR_ERR(panel);  in drm_panel_add_follower()
460 	get_device(panel->dev);  in drm_panel_add_follower()
461 	follower->panel = panel;  in drm_panel_add_follower()
463 	mutex_lock(&panel->follower_lock);  in drm_panel_add_follower()
465 	list_add_tail(&follower->list, &panel->followers);  in drm_panel_add_follower()
466 	if (panel->prepared) {  in drm_panel_add_follower()
469 			dev_info(panel->dev, "%ps failed: %d\n",  in drm_panel_add_follower()
473 	mutex_unlock(&panel->follower_lock);  in drm_panel_add_follower()
481  * @follower:     The panel follower descriptor for the follower.
484  * unprepare function if we're removed from a panel that's currently prepared.
490 	struct drm_panel *panel = follower->panel;  in drm_panel_remove_follower()  local
493 	mutex_lock(&panel->follower_lock);  in drm_panel_remove_follower()
495 	if (panel->prepared) {  in drm_panel_remove_follower()
498 			dev_info(panel->dev, "%ps failed: %d\n",  in drm_panel_remove_follower()
503 	mutex_unlock(&panel->follower_lock);  in drm_panel_remove_follower()
505 	put_device(panel->dev);  in drm_panel_remove_follower()
517  * @follower:     The panel follower descriptor for the follower.
540  * @panel: DRM panel
542  * Use this function to enable backlight handling if your panel
545  * When the panel is enabled backlight will be enabled after a
548  * When the panel is disabled backlight will be disabled before the
551  * A typical implementation for a panel driver supporting device tree
558 int drm_panel_of_backlight(struct drm_panel *panel)  in drm_panel_of_backlight()  argument
562 	if (!panel || !panel->dev)  in drm_panel_of_backlight()
565 	backlight = devm_of_find_backlight(panel->dev);  in drm_panel_of_backlight()
570 	panel->backlight = backlight;  in drm_panel_of_backlight()
577 MODULE_DESCRIPTION("DRM panel infrastructure");